Dry-Type Bushing Current Transformers (DBCTs) can be used for a variety of measuring, revenue metering and protection applications. Peak Demand DBCTs are designed and manufactured in accordance with customer specifications and to IEEE, IEC or GOST standards. Each DBCT is 100% routine tested in accordance to the specified standard and test reports are sent with each order.
Generally used in high voltage circuit breakers, Dry-Type BCTs are installed in either air insulated panels of SF6 chambers to measure primary currents up to 8000A. As there are no standard ratings for DBCTs, each unit is custom designed for its application. In addition to the current ratio, accuracy class and power frequency, some information regarding the equipment must be provided. To determine the physical size the limiting dimensions must be given. These are the minimum ID, the maximum OD and the maximum stack height.
The DBCT core is constructed from wound layers of electrical grade steel or low loss, high accuracy materials, depending on the customer’s specifications. The core is protected with insulation rings to protect the coil winding from damage. Cores are wrapped with coated copper wire to ensure against damage and potential short circuits. The secondary winding, or core and coil assembly, is insulated with a non-porous tape specifically manufactured for dry type environments.
Design and Test
Winding wire is terminated with either leads or terminal connections per the customer specification. Various types and sizes of lead wires are crimped and soldered with the winding wire to ensure high quality, solid connections. Lead wires are one color or color coded and marked for simple connections as per customer requirements. Standard tests include accuracy, polarity, double induced, di-electric, turns-ratio, and excitation for every unit. Each OBCT has a unique serial number which allows the customer to track each test record. Certified test reports are provided with every DBCT shipment.
Packaging and Shipping
Packaging and shipping options such as collapsible and returnable crates and direct shipment are available upon customer request.
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